In horology, the part normally used for adjusting the main functions of a timepiece is called the crown. In a watch, the crown is usually mounted on the side of the watch middle, the middle being the part containing the system which enables the time to be displayed on the dial.
There are in addition two major classes of time-measuring system used in horology for mounting in timepieces, specifically in watch cases. On the one hand are electronic systems, known as quartz movements, which are usually battery-powered and comprise a quartz oscillator and electronic components mounted in an electronic circuit which measures and displays the time accurately. On the other hand are mechanical systems which are usually self-powered, requiring the use of no battery and generally having a spring, termed the hairspring, and a number of mechanical components, chiefly gears, mounted in a mechanical system known as the movement. Generally speaking the crown is for adjusting, activating or deactivating the functions of the movement of a timepiece, usually by means of a rod which connects it kinematically to the movement of the timepiece.
The invention applies particularly to mechanical watches comprising a crown for adjusting and/or controlling the movement. In a mechanical watch the case is the assembly composed of the case back, the middle and the part that provides the connection between the case and the watch crystal, which is known as the bezel.